"The end of the spring I think is technically 21 June. We haven't heard yet and of course in a couple of weeks' time Parliament recesses for the summer.

"So we're very hopeful that the government will respond before Parliament goes down for the summer break."

He said the commission backed the proposals unanimously and "we'd like to see those being implemented pretty rapidly".

He said there was speculation the proposals were being considered alongside devolution considerations in England but warned tackling everything in one go could be "complex".

Dr Gwilym said the commission's 33 recommendations for Wales were "relatively straight forward" and all but one of the tax matters were already devolved to Scotland, adding: "If they're devolved to Scotland, why not to Wales?"

'Implications for UK'

He added that commission members were due to meet Welsh Secretary David Jones MP on Thursday.

In response to Dr Gwilym's comments, Mr Jones said: "The Silk Commission made 33 detailed recommendations that would fundamentally alter the Welsh devolution settlement in terms of financial powers.

"They have implications for the whole of the UK, not just for Wales, and it is right that we take as much time as necessary to consider fully the implications.

"We will respond as soon as possible."

David Davies, Conservative MP for Monmouth, said he suspected the UK government would "link their response to their response to what goes on in England as well".

He said he was "certainly unhappy" with some of the Silk Commission's recommendations and he would be "very interested to see what the response of the government is".

Earlier this week, deputy Prime Minister Nick Clegg told MPs that supporters of more devolution would be "pleasantly surprised" by the UK government's "forthcoming and forward-leaning approach".